[JavaScript] diff_prettyHtml highlight leading/trailing space difference

[54mu3l]

diff_prettyHtml currently doesn't highlight leading/trailing space differences. Because spaces in HTML aren't visible.

This pull request changes that.

Instead of

<insstyle="background:#e6ffe6;"></ins>

diff_prettyHtml now returns

<insstyle="background:#e6ffe6;">&nbsp;</ins>

resulting in differences with leading/training spaces being visible in HTML.

---

Example:
When we compare Test and Test (notice the second string doesn't equal the first string since it has a trailing space).

vardiff=dmp.diff_main("Test","Test ");// this results in the following diff: [[0, 'Test'], [1, ' ']]

Previously looked like this:

Now with this pull requests it looks like this: